Generally, backpacks used for back-mounting compressed-air cylinders include a flat backboard, with shoulder harnesses, a waist belt and a cylinder fastening belt integrated with the backboard into a single structure. To back-mount a compressed-air cylinder using such a backpack, the compressed-air cylinder is fastened to the backboard using the cylinder fastening belt, and thereafter, a user back-mounts the compressed-air cylinder by wearing both the shoulder harnesses on his/her shoulders and the waist belt around his/her waist.
As shown in FIG. 1, a conventional backpack comprises a backboard 10 to which a compressed-air cylinder 50 is fastened in a vertical position, with shoulder harnesses 30 and a waist belt 20 having a buckle 24 all being coupled to the backboard 10.
Harness locking holes 11 are formed on an upper portion of the backboard 10. The upper end of each harness 30 passes through each harness locking hole 11 and is sewn along a line S, thus being coupled to the locking hole 11. A cylinder fastening belt 40 is coupled to a middle portion of the backboard 10 to fasten the compressed-air cylinder 50 to the backboard 10. A back belt 21 having clips 22 at both ends thereof is coupled to a lower portion of the backboard 10, and is worn around the back of the waist of a user, with the waist belt 20 coupled to the clips 22.
In the backpack, the back belt 21 is inserted into back belt passing holes 11a formed on both sides of the backboard 10, of which the intermediate portion is placed on the backboard 10 as shown by the dotted line in the drawing. The lower end of each harness 30 is sewn along another sewn line S to be attached to each of the outside parts of the back belt 21 having the clips 22.
Because the lower ends of the harnesses 30 are sewn to the outside parts of the back belt 21 along the horizontal sewn lines S, respectively, the lower ends of the harnesses 30 are placed parallel to the lengthwise axis of the back belt 21.
The lower ends of the harnesses 30 are sewn to the back belt 21 along the sewn lines S as described above. Thus, the harnesses 30 are integrated with the back belt 21 and, furthermore, the backboard 10 is integrated with both the harnesses 30 and the back belt 21 into a single structure.
A pair of support hooks 12 is provided on the center of a lower portion of the backboard 10 and supports the neck part of the air cylinder 50 having a regulator 56. An L-shaped metal support frame 15, which is produced separately from the backboard 10, is mounted to the lower end of the backboard 10 through a bolting process. Due to the support frame 15, a user may support the backboard 10 on a support surface while wearing the harnesses 30.
Flashing lamps 13 to indicate a user,s, location are provided on the backboard 10 at opposite sides of the pair of support hooks 12. A battery casing 14 to hold therein batteries to supply electricity to the flashing lamps 13 is provided on the lower portion of a back surface of the backboard 10 at a position near the flashing lamps 13.
In the drawing, the reference numeral 55 denotes an air hose that is connected to the regulator 56 of the compressed-air cylinder 50.
To back-mount the compressed-air cylinder 50 using the above-mentioned backpack, the compressed-air cylinder 50 is placed on the backboard 10 in an upside-down position, with the neck of the cylinder 50 supported by the support hooks 12. The cylinder 50 is, thereafter, fastened to the backboard 10 by the cylinder fastening belt 40.
After setting the backboard 10 on the support frame 15, the user back-mounts the compressed-air cylinder 50 by wearing the harnesses 30 and the waist belt 20.
However, when the user with the conventional backpack on his/her back bends his/her upper body to the left or right, the back belt 21, the waist belt 20, the harnesses 30 and the backboard 10 which are integrated into a single structure move along with the bending motion of the user's body. Thus, the compressed-air cylinder 50 leans in the same direction and at the same angle as the upper body of the user.
Due to the leaning of the compressed-air cylinder 50, the center of gravity of the cylinder 50 is shifted to cause the user to easily fall in the direction that the air cylinder 50 is leaning.
Particularly, when the user of the backpack is a fireman and falls due to the change in the center of gravity of the compressed-air cylinder 50 on the scene of a fire, the user may meet with misfortune.
Furthermore, in the conventional backpack, the harnesses 30 are coupled to the back belt 21 to form an integrated structure. Thus, when the user with the backpack raises his/her arm, the back belt 21 tensions the harnesses 30. Consequently, the harnesses 30 press the shoulders of the user. Thus, the user with the backpack is inconvenienced while using his/her arms due to the restriction caused by both the back belt 21 and the harnesses 30.
In addition, because the battery casing 14 is provided on the back surface of the backboard 10, the user must remove the backpack when needing to exchange the batteries for new ones. Thus, it is inconvenient to ex change the batteries for new ones and excessive time must be consumed while changing the batteries.
Furthermore, the support frame 15 to support the backboard 10 is shaped as an angled structure that may easily catch on protruding objects, such as steel reinforcing bars, while the user with the backpack on his/her back moves around a place. Also, the support frame 15 is made of iron, resulting in an increase in the weight of the backpack.
When the support frame 15 of the backpack catches on a protruding object while the fireman is putting out a fire, the fireman must release the support frame 15 from the protruding object, delaying the extinguishing work. Furthermore, due to the support frame 15 which may easily catch on protruding objects, the fireman may have difficulty quickly escaping from danger at the scene of a fire.
Furthermore, because the support frame 15 is produced separately from the backboard 10, the support frame 15 must be attached to the backboard 10 through an additional process that increases the time required to produce the backpack.
The consumption of excessive time during backpack production process results in a reduced quantity of backpacks being produced.